Dicarboxylic acids include two carboxylic acid groups and have a number of uses including, but not limited to, food additives, polymer plasticizers, solvents, lubricants, engineered plastics, epoxy curing agents, adhesive and powder coatings, corrosion inhibitors, cosmetics, pharmaceuticals, and electrolytes. Such dicarboxylic acids can also be converted into their ester forms for a different variety of different uses.
Dicarboxylic acids such as malic, fumaric and succinic acids can be produced by chemical synthesis or fermentation. Since the production of dicarboxylic acids by chemical synthesis can result in harmful waste by-products, a need exists for the production of dicarboxylic acids by fermentation.
Malic acid is an organic acid having utility in the food production industry and is used for making cosmetics. Malic acid is also used in the chemical industry as a surfactant or biodegradable polymer. The malic acid can also be subjected to various processes to product hydroxybutyrolactone and hydroxysuccinate derivatives, maleic anhydride and 1,4-butanediol.
Fumaric acid is an organic acid widely found in nature. In humans and other mammals, fumaric acid is a key intermediate in the tricarboxylic acid cycle for organic acid biosynthesis (also known as the Krebs cycle or the citric acid cycle). Fumaric acid is also an essential ingredient in plant life and finds utility in the food industry; as a chemical intermediate in the production of malic acid and aspartic acid; as an industrial chemical in the manufacture of polyester resins or polyhydric alcohols; as a mordant for dyes; or can be used in the production of a wide variety of industrial chemicals.
Succinic acid is an organic acid finding utility as a surfactant, a detergent, an extender or a foaming agent. Succinic acid can also be an ion chelator, used in the food or feed industry, used in the pharmaceutical or health products markets or as a plant stimulant. Like malic acid and fumaric acid, succinic acid can also be used as an industrial chemical such as in the production of adipic acid, 4-amino butanoic acid, aspartic acid, 1,4-butanediol, diethyl succinate, ethylenediaminedisuccinate, fumaric acid, gamma-butyrolactone, hydroxysuccinide, itaconic acid, maleic acid, maleic anhydride, maleimide, malic acid, N-methylpyrrolidone, 2-pyrrolidione, succinimide, tetrahydrofuran or other 4-carbon compounds. Succinic acid can also be used for producing biodegradable polymers.